CN102685638B - Method and apparatus for outputting audio signal - Google Patents
Method and apparatus for outputting audio signal Download PDFInfo
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- CN102685638B CN102685638B CN201210061834.4A CN201210061834A CN102685638B CN 102685638 B CN102685638 B CN 102685638B CN 201210061834 A CN201210061834 A CN 201210061834A CN 102685638 B CN102685638 B CN 102685638B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/351—Pulse width modulation being used in an amplifying circuit
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
- H03F3/217—Class D power amplifiers; Switching amplifiers
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- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
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Abstract
An audio signal outputting apparatus and method are provided. The audio signal outputting apparatus includes: a pulse width modulation (PWM) unit which generates a carrier signal, compares a signal level of the carrier signal with a signal level of an audio signal, and generates a PWM signal based on a result of the comparison; a controller which, based to a level of the audio signal, controls the PWM unit to change a signal shape of the carrier signal to adjust a duration of a logic high level of the PWM signal; and a switching power unit which amplifies the PWM signal generated by the PWM unit and outputs the amplified PWM signal.
Description
This application claims being submitted to the 10-2011-0021045 Korea of Korean Intellectual Property Office on March 9th, 2011
The priority of patent application, the disclosure of this application is completely integrated in this by reference.
Technical field
The apparatus and method consistent with exemplary embodiment are related to exports audio signal, more particularly, are related to export sound
Frequency signal is improving the speed of service.
Background technology
Audio-frequency power amplifier (amps) receives audio signal and exports earcon, and audio-frequency power amplifier is generally divided
Class is A classes, B classes, AB classes and D classes.Here, D class power amps are widely used, this is because with A class power amps, B class work(
Rate amps is compared with AB class power amps, reduces the deterioration of amplification efficiency.D class power amps is by converting audio signals into
Pulse width modulation (PWM) signal carrys out switched audio signal.D class power amps are also referred to as digital amplifier.
Digital amps is because such as little data conversion loss is extensive with the characteristics of 100% theoretical amplification efficiency
Use.In such digital amps, it is important that defeated in the case where distorted signals are not produced according to peak power output
Go out the audio signal of input.
The content of the invention
One or more exemplary embodiments provide the output gain for the quick adjustment audio signal in no-delay ground
The method of exports audio signal, and the equipment that exports audio signal is come by using the method.
One or more exemplary embodiments are additionally provided for adjusting sound while the deterioration of audio quality is minimized
The method of the exports audio signal of the output gain of frequency signal, and the equipment that exports audio signal is come by using the method.
According to the one side of exemplary embodiment, there is provided a kind of audio-frequency signal output apparatus, including：Pulse width modulation
(PWM) unit, produces carrier signal, compares the signal level of carrier signal and the signal level of audio signal, and based on comparing
Result produce pwm signal；Controller, based on Audio Meter, controls the signal shape that PWM units change carrier signal
To adjust the persistent period of the logic high of pwm signal；Switching power supply, amplifies the pwm signal produced by PWM units simultaneously
The pwm signal that output is amplified.
When Audio Meter is higher than predetermined fiduciary level, the controllable PWM units of controller change carrier signal
Signal shape reducing persistent period of the logic high of pwm signal.
When Audio Meter is less than predetermined fiduciary level, the controllable PWM units of controller change carrier signal
Signal shape increasing persistent period of the logic high of pwm signal.
Controller may also include：Memory element, stores the signal with regard to carrier signal corresponding with Audio Meter
The information of shape.
The controllable PWM units of controller change the signal shape of carrier signal, with for different audio signal electricity
The persistent period of the logic high of each signal level time period adjustment pwm signal of the audio signal of flat scope.
Controller can control PWM units and change carrier signal in the first time period of the zero passage that audio signal occurs
Signal shape is reducing persistent period of the logic high of pwm signal.
Controller can be equal to or higher than the upper limit of first time period and less than or equal to predetermined in Audio Meter
Fiduciary level second time period in, control PWM units and change the signal shape of carrier signal to increase the logic of pwm signal
The persistent period of high level.
Controller can be equal to or higher than in the 3rd time period of the predetermined fiduciary level in Audio Meter, control
PWM units processed change the signal shape of carrier signal to reduce the persistent period of the logic high of pwm signal.
Audio-frequency signal output apparatus may also include：Loop filter, detects the output level of the pwm signal for amplifying, and supervises
Whether the big pwm signal of measuring exceedes Maximum Output Level.
Controller can receive monitoring result from loop filter, and when the level of the pwm signal for amplifying exceedes maximum output
During level, controller can change the signal shape of carrier signal to reduce the persistent period of the logic high of pwm signal.
According to the one side of another exemplary embodiment, there is provided a kind of method of exports audio signal, including：Detection sound
The level of frequency signal；The carrier signal with the signal shape changed based on the Audio Meter for detecting is produced, to adjust
The persistent period of the logic high of whole pwm signal；Compare the signal level of carrier signal and the signal level of audio signal；Base
Pwm signal is produced in result of the comparison；Amplify pwm signal and export the pwm signal of amplification.
Description of the drawings
By referring to detailed description of the accompanying drawing to exemplary embodiment, above and other aspect will become apparent,
Wherein：
Fig. 1 is the block diagram of the audio-frequency signal output apparatus according to exemplary embodiment；
Fig. 2 is the detailed diagram of pulse width modulation (PWM) unit of the Fig. 1 according to exemplary embodiment；
Fig. 3 illustrates the example of the carrier signal and pwm signal produced according to the PWM units by Fig. 2 of exemplary embodiment；
Fig. 4 illustrates the carrier signal that produced by the PWM units of Fig. 2 according to another exemplary embodiment and pwm signal
Example；
Fig. 5 illustrates the carrier signal that produced by the PWM units of Fig. 2 according to another exemplary embodiment and pwm signal
Example；
Fig. 6 is illustrated in detail in carrier signal and the pwm signal produced according to the PWM units by Fig. 2 of exemplary embodiment
Example；
Fig. 7 is the audio-frequency signal output apparatus corresponding with the audio-frequency signal output apparatus of Fig. 1 according to exemplary embodiment
Detailed diagram；And
Fig. 8 is the flow chart of the method for the exports audio signal according to exemplary embodiment.
Specific embodiment
Hereinafter, exemplary embodiment is described with reference to the accompanying drawings.However, exemplary embodiment can in many different forms by
Realize, and should not be construed as being limited to exemplary embodiment set forth herein；More properly, there is provided these exemplary enforcements
Present inventive concept and fully can be conveyed to those skilled in the art so that the disclosure would is that thorough and complete by example
Member.In the accompanying drawings, identical label represents identical element.Hereinafter, when such as " at least one " expression be located at the unit that lists
When after part, the discrete component that the element rather than modification that its modification is all listed is listed.
Audio-frequency amplifier system or audio-frequency signal output apparatus may be designed to have based on predetermined incoming level most
Big output.In some cases, audio-frequency signal output apparatus can be received with higher than the audio signal of the level recording of fiduciary level.
In this case, the amplifier of exports audio signal receives too high input in audio-frequency signal output apparatus.
When with higher than fiduciary level level recording audio signal with maximum loudness level (maximum volume
Level when) reproduced, audio-frequency signal output apparatus perform the operation more than maximum output.That is, it may occur that slicing
(clipping).This operation may destroy the internal part of audio-frequency amplifier system, such as, digital amplifier, speaker, switch
Mode power (SMPS) etc..For example, speaker may be burned out or cut off and therefore can not produce sound.Due to audio frequency amplifier
The circuit of the increase of the internal temperature of system, SMPS or digital amplifier is likely to be broken.
In order to prevent audio-frequency signal output apparatus from performing the operation more than maximum output, output gain is can control.Numeral is put
Big device by pulse width modulation (PWM) come the output of control signal, and can be compressed, extended or be boosted by PWM
(boost) size of audio signal.
Here, the size of compression, extension or audio signal of boosting refers to the gain for changing input audio signal and exports defeated
The audio signal for entering.
In analogy method, can by using variable gain amplifier (VGA) or voltage-adjusting amplifier come control input/
The gain of exports audio signal.On the other hand, in digital method, can be by using individually compression or the signal of extension signal
Process block is controlling the gain of audio signal.
As described above, the output in order to control audio signal, in addition to the part of PWM, also using single amplifier
Or process block.Therefore, will be described in simplifying the process for controlling gain according to one or more exemplary embodiments
Method and apparatus while block for exports audio signal and for minimizing the distortion of audio signal.
Fig. 1 is the block diagram of the audio-frequency signal output apparatus 100 according to exemplary embodiment.
With reference to Fig. 1, audio-frequency signal output apparatus 100 include controller 110, PWM units 120 and switching power supply 130.
Controller 110 receives the signal level of the audio signal that audio signal and detection are received.Additionally, according to detecting
Audio Meter, the control of controller 110 PWM units 120 change the signal shape of carrier signal, add deduct so as to increase
The persistent period of the logic high of few pwm signal.
In detail, when the signal level of detection is higher than predetermined fiduciary level, the control PWM of controller 110 units 120 change
Become the signal shape of carrier signal, so as to the persistent period of the logic high of pwm signal can be reduced.For example, controller 110 can
Detect the average signal level of input audio signal or the peak signal level of audio signal as the signal level of audio signal.
Additionally, controller 110 can determine that the signal shape of carrier signal corresponding with the signal level of the audio signal of detection, and will use
There is the change control signal output of carrier signal of the signal shape for determining in output to PWM units 120.
Here, predetermined fiduciary level is for determining that whether audio signal is the higher limit of such signal：When described
Signal be converted into the signal of pwm signal or the like and by during final output more than audio-frequency signal output apparatus 100 most
Big output.If that is, the signal level of audio signal exceed predetermined fiduciary level, when audio signal is by finally again
Now, the part of audio-frequency signal output apparatus 100 is likely to be broken.Predetermined fiduciary level is designed to be according to possible bag
Peak power output, speaker performance, the reliability of audio frequency apparatus being contained in the product specification of audio-frequency signal output apparatus 100
Deng at least one of and optimised value.
In addition, controller 110 is contemplated that user preferences and changes the signal shape of carrier signal.For example, in audio signal
In the case of with middle level, when user wants the sound for listening higher volume, controller 110 can change the signal of carrier signal
Shape, so as to the logic of middle pwm signal during the time period that predetermined fiduciary level is equal to or less than in Audio Meter
The persistent period of high level can increase.That is, when Audio Meter is equal to or less than predetermined fiduciary level
Between during section, volume may increase.
Controller 110 can store by be mutually matched Audio Meter and with corresponding to the level carrier signal
The relevant information of signal shape and the data base that obtains.For example, what data base can be stored in that controller 110 includes is predetermined
In memory space (not shown), or it is stored in the single memory space (not shown) of audio-frequency signal output apparatus 100.Can
By the manufacturer and at least one of user of audio-frequency signal output apparatus 100 designing or data storage storehouse.
PWM units 120 are produced has the carrier signal of the signal shape changed according to the control of controller 110, and compares
Compared with carrier signal and audio signal producing pwm signal.Detailed construction and the operation of PWM units 120 will be described with reference to Fig. 2 and 3.
Switching power supply 130 amplifies the power of the pwm signal produced by PWM units 120 to be believed with the PWM for producing amplification
Number.For example, switching power supply 130 amplifies the pwm signal of generation according to the maximum output of audio-frequency signal output apparatus 100
Amplitude, and export the pwm signal of amplification.When the audio-frequency signal output apparatus 100 according to this exemplary embodiment are included for putting
During the switching power supply 130 of big pwm signal, it should be understood that another exemplary embodiment not limited to this.For example, according to another example
Property embodiment, switching power supply 130 can be omitted, and audio-frequency signal output apparatus 100 can be believed in the PWM that do not amplifying generation
Output pwm signal in the case of number.In addition, it should be understood that being set according to the output of the audio signal of one or more exemplary embodiments
Standby 100 can export pwm signal to external loudspeaker, another device for processing pwm signal or circuit, the audio signal
Outut device 100 can be using output pwm signals such as internal loudspeakers.
Fig. 2 is the detailed diagram of the PWM units 120 of the Fig. 1 according to exemplary embodiment.
With reference to Fig. 2, PWM units 120 may include carrier-signal generator 210 and pwm signal generator 220.
In response to the change control signal of the input of controller 110, carrier-signal generator 210 is produced corresponding to change control
The carrier signal of signal.The carrier signal with unlike signal shape is exported according to control signal is changed.Here, changing control letter
Number comprising for change carrier signal signal shape information.For example, changing control signal can include with regard to carrier signal sheet
The information of the signal shape of body.If additionally, carrier-signal generator 210 is comprising with regard to the letter of the carrier wave with multiple signal shapes
Number information, then each change control signal can be comprising being used for from multiple carrier signals of different shapes (for example, address letter
Number or the like signal) in read a carrier signal information.
Pwm signal generator 220 receives audio signal and carrier signal, and the signal level of comparing audio signal and carrier wave are believed
Number signal level, and export there is the pwm signal of pulse width modulated according to result of the comparison.Will be detailed with reference to Fig. 3
The generation of thin description pwm signal.
Fig. 3 is illustrated according to the carrier signal produced by the PWM units 120 of Fig. 2 of exemplary embodiment and showing for pwm signal
Example.
Fig. 3 illustrates the situation that the Audio Meter detected by controller 110 is middle level (amplitude of such as half).
For example, when the Audio Meter of detection is middle level, audio-frequency signal output apparatus can not be performed more than its maximum output
Operation.Therefore, it is not necessary to adjust the yield value of audio signal.Additionally, when Audio Meter is average level, it is exportable
Carrier signal is producing the pwm signal that dutycycle remains 50: 50.
When Audio Meter is average level, dutycycle is that the gain in the case of 50: 50 is referred to as unit increasing
Benefit.Additionally, the carrier signal for producing corresponding to the pwm signal of unit gain is referred to as unit gain carrier signal.
In figure 3, X-axis represents time, Y-axis representation signal level.Additionally, signal level can be with voltage (V) as unit.
With reference to Fig. 3, in response to changing control signal, carrier-signal generator 210 is produced and exported corresponding to change control
The carrier signal 310 of signal.
Pwm signal generator 220 may compare the signal level of the signal level of carrier signal 310 and audio signal 320.When
When the signal level of carrier signal 310 is more than the signal level of audio signal 320, pwm signal generator 220 can be with logic low
Level output pwm signal 330.Additionally, when the signal level of carrier signal 310 is less than the signal level of audio signal 320,
Pwm signal generator 220 can be with logic high output pwm signal 330.
For example, the signal level in carrier signal 310 is higher than the time period of t1 to the t2 of the signal level of audio signal 320
In, pwm signal generator 220 is with logic low output pwm signal 330.Audio frequency is less than in the signal level of carrier signal 310
In the time period of t2 to the t3 of the signal level of signal 320, pwm signal generator 220 is with logic high output pwm signal
330。
To describe in detail for output according to the signal level of the audio signal detected by controller 110 with reference to Figure 4 and 5
The PWM units 120 of the carrier signal of change.
Fig. 4 illustrates the carrier signal produced by the PWM units 120 of Fig. 2 and pwm signal according to another exemplary embodiment
Example.
When Audio Meter is less than average record level, the volume for exporting sound can be relatively low, therefore user is to sound
The satisfaction of sound quality can be relatively low.In this case, average record level can be the corresponding sound when maximum output is kept
The exercisable optimum Audio Meter of frequency signal output apparatus.As described above, exporting audio frequency by using digital amplifier
The audio-frequency signal output apparatus of signal are designed to be had based on the maximum output of average record level.
With reference to Fig. 4, show corresponding with when the Audio Meter that controller 110 is detected is less than average record level
Outgoing carrier signal.For example, controller 110 detects the signal level of audio signal.By the signal level of detection and average note
Record level compares, if the signal level of detection is determined to be below average record level, can control carrier signal and produces
Device 210 exports the carrier signal for increasing yield value to increase the volume of output signal.
As shown in Figure 4, controller 110 can control PWM units 120 and change carrier wave letter according to the level of audio signal 420
Numbers 410 signal shape is increasing persistent period of the logic high of pwm signal 430.For example, when the electricity of audio signal 420
It is flat less than average record level when, or for example when the peak level of audio signal 420 is less than above-mentioned predetermined fiduciary level, control
Device processed 110 can control PWM units 120 and change the signal shape of carrier signal 410 to increase the logic high of pwm signal 430
Persistent period.
Compared with Fig. 3, when carrier signal 410 signal shape close to Fig. 4 signal shape when, pwm signal 430 is patrolled
Collecting the persistent period of high level increases.For example, when carrier signal 410 has the signal shape illustrated in Fig. 4, pwm signal 430
It is output with logic low in the time period from t11 to t12, with logic high quilt in the time period from t12 to t13
Output.That is, the signal shape by changing carrier signal 410 according to the control of controller 110, audio signal 420
Gain can increase, and export sound volume also can increase.
Fig. 5 illustrates the carrier signal produced by the PWM units 120 of Fig. 2 and pwm signal according to another exemplary embodiment
Example.
When Audio Meter is higher than average record level, or when the peak level of audio signal is predetermined higher than above-mentioned
Fiduciary level when, audio-frequency signal output apparatus can perform the operation more than its maximum output and be likely to be broken.
With reference to Fig. 5, as shown in Figure 5, controller 110 can control PWM units 120 and change according to the level of audio signal 520
Become the signal shape of carrier signal 510 to increase persistent period of the logic low of pwm signal 530.For example, audio signal is worked as
When 520 level is higher than average record level, or for example when the peak level of audio signal 520 is higher than above-mentioned predetermined standard electric
At ordinary times, controller 110 can control PWM units 120 and change the signal shape of carrier signal 510 to increase the logic of pwm signal 530
The low level persistent period.
Compared with Fig. 3, when carrier signal 510 signal shape close to Fig. 5 signal shape when, pwm signal 530 is patrolled
Collecting the persistent period of high level increases.For example, when carrier signal 510 has the signal shape illustrated in Fig. 5, pwm signal 530
It is output with logic low in the time period from t21 to t22, with logic high quilt in the time period from t22 to t23
Output.That is, by the signal shape of the control break carrier signal 510 according to controller 110, audio signal 520
Gain can be reduced, and can prevent audio-frequency signal output apparatus from performing the operation more than its maximum output.
It is contemplated that the peak power output of audio-frequency signal output apparatus, reliability or the like, experimentally optimization and
The signal shape of design carrier signal corresponding with Audio Meter.Additionally, as described above, can be by from including audio signal
At least one signal shape to design or store carrier signal selected in the manufacturer of outut device 100 and the group of user.
Fig. 6 is illustrated according to the carrier signal produced by the PWM units 120 of Fig. 2 of exemplary embodiment and showing for pwm signal
Example.
Additionally, when controller 110 can change the signal shape of carrier signal with for each signal level of audio signal
Between section adjustment (for example, increasing or decreasing) pwm signal logic high persistent period.
With reference to Fig. 6, the carrier signal exported according to the control of controller 110 can have such signal shape, the letter
Number shape is used for the persistent period of the logic high that pwm signal is increased or decreased for each signal level time period.Fig. 6 shows
Go out the amplifier section of 1/4 time period of carrier signal.That is, the carrier signal illustrated in Fig. 6 is believed corresponding to the carrier wave of Fig. 3
Numbers 310 1/4 time period 340.Additionally, the change of the signal shape in order to describe the carrier signal that controller 110 is carried out, enters one
Step illustrates the single gain carrier signal 620 that signal shape is not changed.
Controller 110 can change the signal shape of carrier signal 610, with the first time period from 0 to V0 (in the time
Section sound intermediate frequency signal level zero passage (zero-crossing)) in reduce pwm signal logic high persistent period.It is logical
Often, it is almost in 0 time period (that is, zero passage) in signal level, there are many noises.Therefore, controller 110 can change carrier wave
The signal shape of signal is reducing the gain in the time period that code is transformed.
With reference to Fig. 6, controller 110 can control the signal shape of carrier signal 610, so that the signal of carrier signal 610
Level can have the value bigger than the signal level of single gain carrier signal 620 in the first time period that code is transformed.Cause
This, the exportable carrier signal 610 with the signal shape illustrated in Fig. 6 of carrier-signal generator 210.Therefore, from 0 to V0
Time period for being transformed of code in, the persistent period of the logic high of pwm signal reduces and is output.
That is, controller 110 can control PWM units 120 and produce being used as reducing gain in first time period
The carrier signal of the compressor of value.
Additionally, controller 110 can change the signal shape of carrier signal 610 to increase pwm signal in second time period
Logic high persistent period, in the second time period, Audio Meter be equal to or more than V0 level and
Less than or equal to V3 level, wherein, V0 level is the upper limit of first time period, and V3 level is predetermined fiduciary level.From V0
Level is in the second time period of V3 level, although volume increases, but audio-frequency signal output apparatus 100 can not be performed more than most
The operation of big output.Therefore, in second time period, by improving volume, user may be lifted to the satisfaction of sound quality.
With reference to Fig. 6, the signal level of carrier signal 610 is less than single gain carrier signal 620 in second time period
Signal level.When the audio signal with V1 level is transfused to, carrier signal 610 can be based on single gain carrier signal 620
The persistent period of the logic high of pwm signal is increased into the time period 650.Additionally, work as that there is V2 level (that is, corresponding to maximum
The half value of signal level V5 of output) audio signal when being transfused to, carrier signal 610 can be based on single gain carrier signal
The persistent period of the logic high of pwm signal is increased time span 651 by 620.
That is, controller 110 can control the generation of PWM units 120 effect similar in second time period (that is, in
Between the signal level time period) in increase yield value booster (booster) carrier signal.
Additionally, controller 110 can change the signal shape of carrier signal, to be equal to or more than V3 in Audio Meter
The 3rd time period in reduce pwm signal logic high persistent period.
With reference to Fig. 6, the signal level of carrier signal 610 is more than single gain carrier signal 620 in the 3rd time period
Signal level.The lower limit of the 3rd time period can be above-mentioned predetermined fiduciary level, and the upper limit of the 3rd time period can be
Corresponding to signal level V5 of maximum output.For example, when the audio signal with signal level V5 is transfused to, audio signal is defeated
Going out equipment 100 can export sound in the sound that can be exported with max volume.
When the audio signal with level V4 is transfused to, carrier signal 610 can be incited somebody to action based on single gain carrier signal 620
The persistent period of the logic high of pwm signal reduces time span 652.
That is, controller 110 can control PWM units 120 and produce being used as reducing gain in the 3rd time period
The carrier signal of the compressor of value.
As described above with described in Fig. 4 to Fig. 6, audio-frequency signal output apparatus 100 change according to the signal level of audio signal
The signal shape of carrier signal simultaneously produces carrier signal.Therefore, can not include or use the independent electricity as adjust gain value
In the case of the compressor or booster of road block, the direct adjust gain value during the generation of pwm signal.That is, passing through
Change the signal shape of carrier signal and produce carrier signal, in the case where the operation of single adjust gain is not performed, can
The direct adjust gain during the generation of pwm signal.
Therefore, the structure of audio-frequency signal output apparatus 100 can be simplified, and can be produced with by the increasing of relatively rapid adjustment
The pwm signal of benefit value.Additionally, power consumption can be reduced by removing the power consumption being used in the independent circuit block of adjust gain value.
As described above with reference to Figure 6, audio-frequency signal output apparatus 100 can remove noise, and can by for it is each each and every one
Other signal level decreases or increases persistent period of the logic high of pwm signal to increase volume.
Additionally, by the signal shape of change carrier signal, audio-frequency signal output apparatus 100 can be exceeded by controlling not perform
The operation of maximum output.It is therefore possible to prevent audio-frequency signal output apparatus 100 are destroyed, and audio-frequency signal output apparatus 100
Operating reliability can be improved.
Fig. 7 illustrates the audio signal of the audio-frequency signal output apparatus 100 corresponding to Fig. 1 according to another exemplary embodiment
The detailed diagram of outut device 700.
With reference to Fig. 7, in addition to the audio-frequency signal output apparatus 100 of Fig. 1, audio-frequency signal output apparatus 700 may also include
Loop filter 740 and loudspeaker unit 750.Controller 710, PWM units 720 and switching power supply 730 are corresponded respectively to
Seen figures.1.and.2 controller 110, PWM units 120 and the switching power supply 130 of description, therefore will omit to them
Detailed description.
Loudspeaker unit 750 receives the pwm signal for being switched on and off the amplification of power subsystem 730, and the pwm signal is converted to into human ear
Audible acoustical signal, and export the acoustical signal.
Loop filter 740 detects the output level of the pwm signal of the amplification from the output of switching power supply 730.Additionally,
Whether the output level of the pwm signal that the monitoring of loop filter 740 is amplified exceedes the maximum output of audio-frequency signal output apparatus 100
Level.
Controller 710 receives the result of monitoring from loop filter 740.Additionally, when the output for determining the pwm signal for amplifying
When level exceedes Maximum Output Level, the control PWM of controller 710 units 720 change the signal shape of carrier signal, to reduce
The persistent period of the logic high of pwm signal.For example, controller 710 can be when audio signal exceedes Maximum Output Level
Between Audio Meter is restricted to into Maximum Output Level in section.Additionally, controller 710 can control PWM units 720 to produce
For reducing the carrier signal of yield value.The generation for reducing the carrier signal of yield value is described with reference to Fig. 5, therefore is saved
Slightly it is described in detail.
Fig. 8 illustrates the flow chart of the method for the exports audio signal according to exemplary embodiment.
With reference to Fig. 8, the electricity of the audio signal that detection is received by controller 110 is included according to the method for exemplary embodiment
Flat (operation 810).
According to the Audio Meter for detecting, change the signal shape of carrier signal to increase or decrease pwm signal
Logic high persistent period, and produce carrier signal (operation 820).For example, controller 110 will can be used to change carrier wave
PWM units 120, and (specifically, the carrier signal product of PWM units 120 are arrived in the change control signal output of the signal shape of signal
Raw device 210) carrier signal can be produced according to the change control signal exported by controller 110.
Compare the signal level of carrier signal and audio signal to produce pwm signal (operation 830).Can be in PWM units 120
In (specifically, in pwm signal generator 220) perform operation 830.
The pwm signal that the power of pwm signal is exaggerated and amplifies is output (operation 840).Operation 840 can be by switch electricity
Source unit 130 is performed.
Additionally, may also include for the pwm signal of amplification to change into acoustical signal and output sound according to the method for the present embodiment
Message number (operation 850).Operation 850 can be performed by loudspeaker unit 750.
Joined with the above according to the technical spirit and operative configuration of the method for the exports audio signal of above-mentioned example embodiment
It is same or like according to the technical spirit and operative configuration of the audio-frequency signal output apparatus of Fig. 1 to Fig. 7 descriptions, therefore it is detailed to omit its
Thin description.
While not limited to this, but implement the computer that exemplary embodiment can be implemented as on computer readable recording medium storing program for performing
Readable code.Computer readable recording medium storing program for performing is that the data of any data that can be stored and can be read by computer system thereafter are deposited
Storage device.The example of computer readable recording medium storing program for performing includes read only memory (ROM), random access memory (RAM), CD-
ROM, tape, floppy disk and optical data storage device.Computer readable recording medium storing program for performing also can be distributed in the computer system of networking,
So as to store in a distributed fashion and computer readable code executed.Additionally, exemplary embodiment can be written as computer journey
Sequence, the computer program is sent by computer-readable transmission medium (such as, carrier wave), and in the general of configuration processor or
Received and implemented in special digital computer.In addition, one or more units of audio-frequency signal output apparatus may include to perform
The processor or microprocessor of the computer program being stored in computer-readable medium.
Although having been described above specifically illustrating and describing exemplary embodiment, one of ordinary skill in the art will
Understand, in the case of the spirit and scope without departing from present inventive concept defined in claim, can be in form and details
Make various changes.
Claims (23)
1. a kind of audio-frequency signal output apparatus, including：
Controller, based on the signal level of audio signal, controls PWM units and changes the signal shape of carrier signal to adjust PWM
The persistent period of the logic high of signal；
Pulse width modulation (PWM) unit, from controller the change control letter for changing the signal shape of carrier signal is received
Number, carrier signal corresponding with the signal shape for changing is produced, by the signal electricity of the signal level of carrier signal and audio signal
It is flat to be compared, and pwm signal is produced based on result of the comparison；
Switching power supply, amplifies the pwm signal produced by PWM units and the pwm signal for exporting amplification.
2. audio-frequency signal output apparatus as claimed in claim 1, wherein, when the signal level of audio signal is higher than predetermined mark
During quasi- level, the logic high that controller control PWM units change the signal shape of carrier signal to reduce pwm signal is held
The continuous time.
3. audio-frequency signal output apparatus as claimed in claim 1, wherein, when the signal level of audio signal is less than predetermined mark
During quasi- level, the logic high that controller control PWM units change the signal shape of carrier signal to increase pwm signal is held
The continuous time.
4. audio-frequency signal output apparatus as claimed in claim 1, wherein, controller also includes：Memory element, store with regard to
The information of the signal shape of the corresponding carrier signal of signal level of audio signal.
5. audio-frequency signal output apparatus as claimed in claim 1, wherein, controller control PWM units change carrier signal
Signal shape, with for each signal level time period adjustment of the audio signal with different audio signal level scopes
The persistent period of the logic high of pwm signal.
6. audio-frequency signal output apparatus as claimed in claim 5, wherein, in the first time period of the zero passage that audio signal occurs
In, controller control PWM units change the signal shape of carrier signal with reduce pwm signal logic high it is lasting when
Between.
7. audio-frequency signal output apparatus as claimed in claim 6, wherein, it is equal to or more than the in the signal level of audio signal
In the upper limit of one time period and the second time period less than or equal to predetermined fiduciary level, controller control PWM units change
Become the signal shape of carrier signal to increase persistent period of the logic high of pwm signal.
8. audio-frequency signal output apparatus as claimed in claim 7, wherein, it is equal to or more than institute in the signal level of audio signal
In the 3rd time period for stating predetermined fiduciary level, controller control PWM units change the signal shape of carrier signal to reduce
The persistent period of the logic high of pwm signal.
9. audio-frequency signal output apparatus as claimed in claim 1, also include：Loop filter, detects the pwm signal of amplification
Output level, and monitor whether the pwm signal of amplification exceedes Maximum Output Level.
10. audio-frequency signal output apparatus as claimed in claim 9, wherein, controller receives the knot of monitoring from loop filter
Really,
Wherein, when the signal level of the pwm signal for amplifying exceedes Maximum Output Level, controller control PWM units change load
The signal shape of ripple signal is reducing persistent period of the logic high of pwm signal.
11. audio-frequency signal output apparatus as claimed in claim 1, also include：Speaker, receives the pwm signal for amplifying, and will put
Big pwm signal changes into acoustical signal, and exports acoustical signal.
A kind of 12. methods of exports audio signal, methods described includes：
The signal level of detection audio signal；
The carrier signal of the signal shape for producing the signal level with the audio signal for being based on detection and changing, to adjust pulse
The persistent period of the logic high of width modulated (PWM) signal；
Compare the signal level of the signal level of carrier signal and the audio signal of detection；
Pwm signal is produced based on result of the comparison；
Amplify pwm signal and export the pwm signal of amplification.
13. methods as claimed in claim 12, wherein, produce and there is the signal level based on the audio signal of detection and change
Signal shape carrier signal the step of include：When the signal level of the audio signal of detection is higher than predetermined fiduciary level
When, change the signal shape of carrier signal, to reduce the persistent period of the logic high of pwm signal.
14. methods as claimed in claim 12, wherein, produce and there is the signal level based on the audio signal of detection and change
Signal shape carrier signal the step of include：When the signal level of the audio signal of detection is less than predetermined fiduciary level
When, change the signal shape of carrier signal, to increase the persistent period of the logic high of pwm signal.
15. methods as claimed in claim 12, also include：Store with regard to corresponding with the signal level of the audio signal of detection
The information of the signal shape of carrier signal.
16. methods as claimed in claim 12, wherein, produce and there is the signal level based on the audio signal of detection and change
Signal shape carrier signal the step of include：Change the signal shape of carrier signal, with for believing with different audio frequency
The persistent period of the logic high of each signal level time period adjustment pwm signal of the audio signal of number level range.
17. methods as claimed in claim 16, wherein, change carrier signal signal shape the step of include：There is sound
In the first time period of the zero passage of frequency signal, change the signal shape of carrier signal to reduce the logic high of pwm signal
Persistent period.
18. methods as claimed in claim 17, wherein, change carrier signal signal shape the step of include：In detection
The signal level of audio signal is equal to or more than the upper limit of first time period and less than or equal to the of predetermined fiduciary level
In two time periods, change the signal shape of carrier signal to increase persistent period of the logic high of pwm signal.
19. methods as claimed in claim 18, wherein, change carrier signal signal shape the step of include：In detection
The signal level of audio signal was equal to or more than in the 3rd time period of the predetermined fiduciary level, changed the letter of carrier signal
Number shape is reducing persistent period of the logic high of pwm signal.
20. methods as claimed in claim 12, also include：The output level of the pwm signal that detection is amplified, and determine amplification
Whether the output level of pwm signal exceedes Maximum Output Level.
21. methods as claimed in claim 20, also include：When it is determined that the output level of the pwm signal for amplifying is defeated more than maximum
When going out level, change the signal shape of carrier signal to reduce persistent period of the logic high of pwm signal.
22. methods as claimed in claim 12, also include：The pwm signal of amplification is changed into into acoustical signal and sound is exported
Signal.
A kind of 23. methods of exports audio signal, methods described includes：
Produce carrier signal；
Compare the signal level of carrier signal and the signal level of audio signal；
Pulse width modulation (PWM) signal is produced based on result of the comparison；
By the logic high for changing the signal shape of carrier signal according to the signal level of audio signal to control pwm signal
Persistent period.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020110021045A KR101871360B1 (en) | 2011-03-09 | 2011-03-09 | Method for outputting an audio signal and apparatus for outputting an audio signal thereof |
| KR10-2011-0021045 | 2011-03-09 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102685638A CN102685638A (en) | 2012-09-19 |
| CN102685638B true CN102685638B (en) | 2017-04-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210061834.4A Expired - Fee Related CN102685638B (en) | 2011-03-09 | 2012-03-09 | Method and apparatus for outputting audio signal |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US9456271B2 (en) |
| KR (1) | KR101871360B1 (en) |
| CN (1) | CN102685638B (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20100008749A (en) * | 2008-07-16 | 2010-01-26 | 삼성전자주식회사 | Switching power amplifier and control method thereof |
| KR101683174B1 (en) * | 2010-01-08 | 2016-12-06 | 삼성전자주식회사 | Method and Apparatus for amplifying audio signal |
| JP2014138221A (en) * | 2013-01-15 | 2014-07-28 | Funai Electric Co Ltd | Digital electronic apparatus, and method for adjusting signal level of digital signal |
| KR101526749B1 (en) | 2013-12-18 | 2015-06-05 | 현대자동차주식회사 | Amplifier docking type vehicle audio system |
| CN104537780B (en) * | 2015-01-19 | 2017-12-01 | 河南辉瑞生物医电技术有限公司 | A kind of impulse waveform modulation circuit |
| CN104518761B (en) * | 2015-01-19 | 2018-01-30 | 河南西瑞医疗电子技术有限公司 | A kind of audio signal edge waveform control circuit |
| GB2560389A (en) * | 2016-12-06 | 2018-09-12 | Cirrus Logic Int Semiconductor Ltd | Methods and apparatuses for driving audio and ultrasonics from the same transducer |
| CN107687891B (en) * | 2017-08-25 | 2020-01-10 | 博众精工科技股份有限公司 | Sound frequency acquisition device |
| US11190148B2 (en) | 2020-01-02 | 2021-11-30 | Cirrus Logic, Inc. | Minimizing idle channel noise in a class-D pulse width modulation amplifier |
| JP2021150655A (en) * | 2020-03-16 | 2021-09-27 | ヤマハ株式会社 | Class D amplifier |
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- 2011-12-09 US US13/316,029 patent/US9456271B2/en not_active Expired - Fee Related
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2012
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| WO2002015393A2 (en) * | 2000-08-14 | 2002-02-21 | Ulrick John W | Digital class-d audio amplifier |
| CN1929300A (en) * | 2005-09-06 | 2007-03-14 | 三星电子株式会社 | Apparatus and method to control audio volume in D class amplifier |
| CN101192810A (en) * | 2006-11-20 | 2008-06-04 | 财团法人交大思源基金会 | A D-category amplifier and method for driving three-line dual track speaker based on it |
Also Published As
| Publication number | Publication date |
|---|---|
| US20120230520A1 (en) | 2012-09-13 |
| KR20120103045A (en) | 2012-09-19 |
| CN102685638A (en) | 2012-09-19 |
| US9456271B2 (en) | 2016-09-27 |
| KR101871360B1 (en) | 2018-06-26 |
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